Currently, a liquid crystal display device generally comprises a backlight module and a liquid crystal panel. The liquid crystal panel covers the backlight module. The backlight module is used as a light source of the liquid crystal panel. The liquid crystal panel can modulate light emitted by the backlight module, so that images and colors can be displayed thereon. With development of liquid crystal display technology, it is required to increase brightness of a display screen as much as possible with power consumption of the backlight module being as low as possible, and meanwhile, it is also required to obtain a high optical grade of the display screen.
As shown in FIG. 1, there are four kinds of sub-pixels in an existing RGBW liquid crystal panel 1a: a red sub-pixel 2a, a green sub-pixel 3a, a blue sub-pixel 4a and a white sub-pixel 5a. A group of the red sub-pixel 2a, the green sub-pixel 3a, the blue sub-pixel 4a and the white sub-pixel 5a constitutes one pixel. Compared with an existing RGB liquid crystal panel, one white sub-pixel 5a is added in order to increase display brightness of the liquid crystal panel and reduce power consumption of the backlight module.
In normal display, only when the red sub-pixel 2a, the green sub-pixel 3a and the blue sub-pixel 4a in a same pixel are all turned on, will the white sub-pixel 5a be turned on. Otherwise, if one of the red sub-pixel 2a, the green sub-pixel 3a and the blue sub-pixel 4a is not turned on, the white sub-pixel 5a will be in an off state.
Therefore, as compared with the RGB liquid crystal panel, when a single color picture or a multiple color picture is displayed on the RGBW liquid crystal panel, the RGBW liquid crystal panel 1a has lower brightness during single color picture display and picture distortion will be resulted in, which will seriously affect the optical grade of the picture.